Azo dye and method of making same



Patented Oct. 4, 1932 1 ,"uNITEo PATENT orrics ERNEST F. GBEI'EER, or MID AND, monrenn, nssreivoa 'ro THE now cnnmcan COMPANY, or nmrinivn, MICHIGAN, A CORPORATION or MICHIGAN AZO DYE Ann METHODOF MAKING same no Drawing. Original application filed an 5, 1928, Seriali to. 290,699. Divided and this application fi1ed October 4, 1929. Serial No. 397,449. I

' The present invention concerns the preparation of .azo dyes from hydroxy-diphenyl compounds and diazo' components, particularly the alkylated dyes. In a previous application, Serial No. 290,699, filed July 5, 1928, of which this is a division, I described such azo dyesand claimed those prepared by combining hydroxy-diphenyl compounds with diazotizedaryl amino bodies. In the present application I shall claim the corresponding azo dyes prepared by alkylating the compounds resulting from couplinghydroxydiphenylswith diazo components, I

I The aforesaid hydroxy-diphenyl compounds are phenolic in character and may be regarded as similar, for example, to the methyl-phenols oricresols, in which a phenyl, instead of a methyl,- group issubstituted in the benzene nucleus, Such phenyl-phenols possess the properties common to, phenols: in general, and are capable of reacting in simi lar ways. Iiorinstance they may be coupled with diazotized, or tetrazotized, aromatic amino bodies forming thereby new and valuable azo dyes. Such dyes in comparison with the corresponding phenol dyes are somewhat deeper in color, and are markedly superior with respect to fastness to light and washing, 'Y

The invention, then, consists of the new product, viz., an azo dyeof the aforesaid character, together with-the steps lnvolved in makingsuch dye hereinafter fully described and particularly pointed out in the claims, the following' description setting forth but several of the various ways in which the principle ofthe invention-may be employed. p

I have found that the operation of coupling either ortho or para-hydroxy-diphenyl with a suitable diazotized aromatic amine, or derivative thereof, may readily be carried out according to the usual methods, the resulting dyes possessing the improved properties already referred to. Further, I have also found thatwhen the hydroxy groups of the hydroxy-diphenyl component of such azo compoundis-alkylated, attaching thereto an alkyl ro'up such as methyl, ethyl or the like, the al kylated derivatives so obtained are dyes exhibiting in even. greater degree the property of fastness to light and washing, as well as further improved color quality. 5

The alk'ylated azo dyes just described, upon treatment with a-reducing agent, are

split at the azo linkage, yielding alkylated amino derivatives of hydroxy-diphenyl compounds which in themselves are capableof being diazotized', and are starting materials for making other azo dyes. Derivatives of thischarac'ter are more particularly claimed in my co-pendingapplication, Serial No. 311,97 6, filed October 11,-1928.

Byway of illustration'the following ex amples are given, but it will be understood that the invention is equally applicable to the preparation of other derivatives of the character in hand. V f 1 I. Sulfanilic acid, 58 parts,is diazotized according-to the usual method and coupled with 50 parts of para-hydroXy-diphenyl dissolved in' 28 parts of caustic soda and 700 parts of water, the mixture beingkept cool and "thoroughly stirreds Common salt is added to precipitate the dye, which is an orange colored crystalline powder; The methyl ether of this compound is then made by adding to the mixture 12 parts of caustic soda and, with stirring, 39 parts of methyl sulphate; The reaction mixture becomes warm and ina short time'forms a thick precipitate. The mass is heated to about 60 C. for about .ZO-minutes, then cooled and the precipitate filtered and washed with salt water; The product is the sodium salt of th'e methyl ether of (benzene para sulfonic acid) -azo-(para-hydroXy-diphenyl) from which the freeacid compound'is obtained by treatment with a mineral acid. Both the acid and its sodium salt consist of bright orange colored crystal flakes, slightly soluble in water, which dye wool directly in orange shades, ,fastto light and washing. The for- I mula of the acid is represented thus II. The analogous dye, derived from ortho-hydroXy-diphenyl by coupling with diazotized sulfanilic acid and subsequent methylation, is produced in an entirely similar manner to that described in Example I. The product has the formula OCH:

This compound is likewise a fine crystalline orange colored powder, somewhat soluble in water. Both the azo compound and the methyl ether thereof dye wool a clear orange color, distinctly deeper in shade than in the case of the para-hydroxy-diphenyl derivatives.

It is a characteristic ofthe dye just described, both of the azo- (hydroxy-diphenyl) compounds and of the alkyl ethers thereof, and equally of the free sulphonic acids and the salts of such acids, that they'are more sparingly soluble in water than are the corresponding derivatives of other phenols, and in contradistinction of such latter derivatives, can be readily crystallized from aqueous solution in substantially pure condition, thus affording a convenient method of separating and purifying such dyes.

- By similar methods related monoand polyazo compounds can be made by coupling orthoor para-hydroxy-diphenyl coma pounds with other diazotized, or tetrazotized, bodies or derivatives thereof.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the method herein disclosed, provided the steps orproducts stated. by any of the following claims, or the equivalent employed.

I therefore particularlypointout and distinctly claim as my invention 1. The method of making an azo dye, which comprises coupling a mono-hydroxydiphenyl with a diazotized aromatic amino compound and alkylating the hydroxyl group of the resulting azo compound.

2. The method of making an azo dye, which comprises coupling a mono-hydroxydiphenyl with an alkali-soluble diazotized aromatic amino compound, and alkylating the hydroxyl group of the resulting azo compound. i

3. The method of vmaking an azo dye,

of such, be

which comprises couplinga mono-hydroXy-.

diphenyl with diazotized sulfanilic acid and alkylating the hydroxyl group of the result ing azo compound.

4:. The method of making an azo dye, which comprises coupling a mono-hydroxydiphenyl with a diazotized aromatic amino compound and, methylating the hydroxyl group of the resulting azo compound. 7

5. The method of making an em dye,

which comprises coupling a mono-hydroxydiphenyl with diazotized sulfanilic acid and methylating the hydroxyl group of the resulting azo compound.

7. As anew product, an alkylated hydroxydiphenyl azo dye characterized by being crystallizable from aqueous solution, and dyeing wool directly and being substantially fast to light and washing.

' :8. As a new product, a methoxy diphenyl azo dye characterized by being crystallizable from aqueous solution in substantially pure condition, and dyeing wool directly in orange shades substantially fast to'light andwashing. 1 9. As a new product, an azo dye having the probable formula, 7

H Oalkyl wherein R represents an aromaticresidue.

10. As a new product, an azo dye having the probable formula,

V Oalkyl p T V I wherein R represents'an alkali-soluble aromatic residue. 7 r

.11. Asanew product,.an azo dye having the'probable formula, V 1

1 2. As a new product, an azo dye having the probable formula,

, 00 i C 3 N=N-R wherein R represents an aromatic residue.

v13. As a new product, an azo dye having the probable formula,

- OCH} i V N=N 7 801B 15. As a new product, an azo dye having the probable formula,

' wherein the alkoxy group is orthoor parato the phenyl group, and R represents an aromatic residue. r 16. As a new product, an azo dye having the probable formula,

O Oalkyl V QI=N-1V wherein the alkoxy group is orthoor parato the phenylgroup, and R represents an alkali-soluble aromatic residue.

17. As a new product, an azo dye having the prob-able formula, V

0 alkyl m wherein the alkoxy group is orthoor parato thephenyl group. 7

18. As a new product, an azo dye having the probable formula,

V OCH: W

wherein the methoxy group is orthoor parato the phenyl group, and R represents an aromatic residue.

19. As a new product, an azo dye having the probable formula,

' \N=NR' wherein the methoxy group is orthoor parato the phenyl group and R represents a sulfonated aromatic residue.

20. As a new product, an azo dye having the probable formula, v

wherein the methoxy group is orthoor parato the phenyl group.

Signed by me this 28th day of September, 1929.

ERNEST F. GRETHER. 

